Single vessel blast furnace and steel making/gasifying apparatus and process

ABSTRACT

A blast furnace for use in an apparatus such as a steel making apparatus or a gasifier includes a vessel including a crucible. The furnace includes a lance for introducing fuel and oxygen into the crucible and instrumentation for determining density characteristics of molten material inside the crucible. In one embodiment, the blast furnace is able to adjust the input of fuel and/or oxygen into the crucible based on the measure density characteristics of the molten material. The blast furnace can also include structure for cooling and clinkering molten material discharged from the crucible.

CROSS REFERENCES TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.60/644,055, filed Jan. 15, 2005.

BACKGROUND OF THE INVENTION

This invention relates to the control of continuous and directiron-making or gasification using ground coal, iron ore (whereapplicable), flux and other materials and unique sensors and computercontrol techniques and methods in a continuous gasification or smeltingprocess through the judicious application of these specialized sensorsand techniques to make an efficient and compact and less costlytechnology, whether making steel or syngas, that does not require peopleto interface with the process directly whereby they are needed only tokeeping the lock hoppers full of feed ingredients, two lock hoppers areused for each ingredient to insure continuous and interrupted feeding ofmaterials, and to keep equipment in good repair.

Much of present steel making is manually controlled with manual samplingof steel quality, manual control of molten levels within the furnace,long time lags, high expense of apparatus since coke and recuperator andother equipment not required of this invention are needed. Also, laborcosts are higher with existing technology. Present steel-makingapparatus, not being continuous, are not as well suited to recovery ofslag materials, which is made easier with continuous and separatelycontrolled molten slag and metal outflows, including metal recovery fromthe coal or carbon gasifiers if syngas is the product i.e. gasificationof carbonaceous materials.

Present gasification apparatuses lack the simplicity of a molten bedapproach plus the sophistication of the sensors and controls of thepresent invention. Existing processes are generally classified as fixedbed, traveling bed, fluidized bed, and entrained flow, and none of theseprocesses has evolved into a market-leader technology.

DESCRIPTION OF RELATED ART

This invention relates to and improves on the inventions described inthe inventor's previous filings, U.S. Provisional Patent Application No.60/629,486 and U.S. Provisional Patent Application No. 60/635,117, byteaching less expensive and alternative methods of molten slag andmolten steel layers level sensing and control. Whereas the referencedinventions show use of scanning nuclear or x-ray gages for this purpose,this invention teaches other lower cost proximity or point levelinstrumentation which when combined with sample-data control techniqueenables full control over molten slag and steel levels or thickness.Other alternative sensors that can be used are insitu laserspectrometers in the molten masses and other insitu point level sensorsbased on magnetic, capacitance, or inductive methods, and even floats,to sense molten slag and steel thickness. For example, the insitu laserspectrometer sensor can be used to control molten slag and steel levelsor thickness because the material makeup is different for molten slagand molten metal, and such a sensor can determine this, but that sensorcan also provide valuable composition information simultaneously andadvantageously. Different signal characteristics will show up for theother types of point sensors mentioned for different materials presentproviding other means to control these levels or thickness. And whencombined with instruments to sense the emitted gases can gain fullcontrol to optimize the gasification and steel-making processes. Whichof these sensor types would be the preferred method is difficult tojudge at this times since for some, like insitu laser spectrometers thecosts will likely be high since they are not in use at this time, beinga new insitu laser spectrometry invention, it is just being introducedsuch as the gas laser spectrometry sensor. However, these sensors haveimportant advantages making their high cost fully justified for largemachines. But this invention claims the use of these specialized sensorsfor the purposes set forth above and in conjunction with othertechnology cited in the references furthering the art and advancesclaimed by the inventor to achieve low cost and reliable syngas andsteel-making technologies based on continuous processes and inparticular using molten slag bed processes and technology for syngasproducing purposes.

SUMMARY OF THE INVENTION

A continuous smelting/low-grade steel making process and/or coal orcarbon gasification process and apparatus involving blasting a mixtureof ground ore, coal, and a flux mixture(s) (or coal and flux and pureoxygen if a syngas gasifier) through a concentric water cooled downwardlance close into the molten slag, with feed mix flowing between theouter cooled shell and inner core air blast tube which expels air/oxygenmixture at high velocity onto the top of the molten slag layer to makesteel or syngas. Further, to make steel there is an air/oxygen blastunder the molten metal layer from the base of the crucible distributedevenly through a fine bubbling diffuser mounted within the cruciblefloor so as to reduce carbon in the molten iron to make at least a lowgrade steel. For syngas making, ground coal or carbon and flux mixtureis blasted into the molten slag with pure oxygen. Means to separatelymeter ore or gasifier mix ingredients from lock hoppers withbubble-tight valves with gas purging to prevent gas from flowing backthough the hoppers, and with in-line mixer before entering theconcentric lance with O2 or enhanced air-O2 mixture (steel). To preheatthe air/oxygen blast for steel-making, circulates blast air mixturewithin a top metal plenum of the furnace with inner shell made of hightemperature coated steel alloys enabling achievement of sufficienttemperature air/oxygen blast. Slag and low-grade steel outlet troughwith above laser spectrometer measurements or insitu laser spectrometersensing slag and steel quality determining chemical composition of bothslag and steel flows to enable optimization of steel quality andminimize carbon losses and control molten levels. Other means arepresented to measure crucible molten slag and molten metal thickness toenable control for molten slag and metal thickness through an out-flowcontrol valve. All this instrumentation is provided so as to combine andwith suitable computer control and optimizing algorithms and software toproperly control preheated ore mix feed rate and composition, levels ofmolten iron, air/oxygen blast rates, and all to produce a quality syngasor low-grade steel output with proper carbon, sulfur and potassiumcontents to the maximum practical extent so as to optimize steel makingor gas quality within one vessel in terms of quality and productionrequirements and to maximize the overall cost effectiveness of processof gas making smelting and steel-making.

As a steel-making invention it is a simple, compact cost-effectivetechnology designed to co-generate electricity and fully automatesteel-making in a single vessel process and apparatus. The process alsoeliminates the need for coke and thus coking ovens, awkward air blastpreheat apparatus, air pollution apparatus (since co-generation boilershandle all flue gas), all which makes steel-making compact and lesscostly with minimized pollution and maximized revenue capability.

This invention teaches use of a molten bed of slag to O2 or enhancedair/O2 blast in ingredients, simplifying operations and improvingcontrol while simplifying slag and metal (if present) rejection andrecovery, or simplified steel-making. Advantages of this newgasification process and apparatus over present apparatus and processesare:

-   -   1. Dry fuel feed. This means maximum hot gas efficiency        potential, approaching 98% and minimized pure oxygen needed to        gasify, minimizing oxygen operating costs.    -   2. Due to the large molten slag bed mass, there is a        flywheel-effect that helps keep the process going as a stable        and intense reaction that can work for any carbon fuel, even the        worst quality coals.    -   3. The simplicity of the molten bath also seals off the drop leg        of the contiguous hot gas cyclone cleaner, a critical advantage        for both gasifying and steel-making since this cyclone hot gas        cleaning is required to achieve low carbon loses and simplify        downstream gas clean-up.    -   4. Blasting fuel and oxygen into the slag mass splatters the        slag onto the gasifer inner walls protecting the refractory and        upper zone interior of the gasifier, which is a proven technique        of the steel industry. This is critical to extending the life of        the refractory for years of use between rebuilds.    -   5. The ability to gasify any carbon material, even the poorest        quality coal, is very important since many regions of the world        do not have high quality coal. To do this, the control computer        automatically adjusts feed ingredient ratios and oxygen blast        and opens up the slag discharge valve more to let out the        greater slag produced from the greater dirt in the coal or waste        fuel. The new sensors and computer does it all automatically,        including sensing and controlling the molten slag and/or steel        bed thickness.    -   6. It also has the ability to fully recover metals that sink to        the bottom under the molten slag mass. A thicker metal bath is        maintained if making steel.    -   7. It also enables recycling slag into construction products.        Since flux (limestone) is added as part of the combustion        process to produce a cleaner gas to react out sulfur (if coal is        used), and since flux is definitely added when making steel, the        heat converts the flux into cement ingredients within the slag.        So if the slag is air dried into clinkers and ground up and kept        under cover like in cement plants, it becomes a concrete product        base material useful to constructing buildings and roads, etc.    -   8. It uses a simple feed apparatus which also enhances        reliability.    -   9. It uses new sensors and sophisticated controls to keep a        close watch over all key process variables. Computer control is        essential to optimizing and controlling basic process and is        absolutely essential to maintain reliability and hands-off        automation. The computer also enables software to be developed        to optimize the process. This is a new standard of        instrumentation being brought into steel-making and gasification        processes to make them reliable and cost effective technologies.

To insure continuous feed, this process includes at least two (2) lockhoppers (not shown) for each ingredient of combination of similaringredients such as ground coal, ore, and fluxes. Three for eachingredient provides needed redundancy for maximized reliability infeeding. These lock hoppers have specially designed variable speedflotation helical undercutting rotors, or the equal are alsocommercially available in the marketplace, to undercut andsimultaneously unload and regulate feeds after calibration with rotaryrpm measurement to flow to maximize production consistent with steel orsyngas desired quality. More than one flux material lock hoppers may beadded to control sulfur and phosphorous content of the finalcommon-grade steel output for example. In gasification, a flux would beadded if there was sulfur present in the carbonaceous fuel, such as incoal, and the lock hoppers would be evacuated of air before rechargingwith an un-reactive gas which also is easily removed later, such a CO2,whereby the feed lock hopper valve can be reopened and the now gaspurged feed made to the ingredient mixer (not shown) commence. The lockhoppers would use bubble tight high-temperature valves on their inletand outlet that are capable of hundreds of thousands even over a millionoperating cycles, such a valve made by Macawber EngineeringIncorporated, which are especially suited to feed applications. Toinsure that no O2 or enhanced air with O2 blast (when making steel) canpass up into lock hoppers, to avoid possible dust explosions in the coallock hoppers in particular when filling, they can be continually CO2purged when feeding, as noted.

As noted, there is an in-line mixer (not shown) that feeds into theconcentric water cooled lance entering through the center top of thesteel-making furnace and/or gasifier. All ingredients converge bygravity flow or other means at this point for gravity flow into themolten slag mass through the water cooled copper lance of sufficientdiameter to accommodate solid material flow in it's outer concentricperimeter and O2 enhanced air flow for steel making in it's center tubeor nearly pure O2 blast flow if gasifying coal or carbonaceous materialsinto syngas. Iron is converted into common-grade steel in the lowermolten metal zone by bubbling in oxygen and molten metal is dischargedfrom a center tap hole on the center floor of the crucible. The exactlocation of the tap hole, which can be out the side as well, is notcritical as long as it is below the slag layer about 12 inches.

The lance outer shell is water cooled with re-circulating water in thecase making steel, or this flow is emitted as a radial water or steamfrom the lower end and perimeter of the lance spraying radially in ahorizontal fashion from the bottom of the lance to create gasificationreactions of ionized carbon into syngas. The amount of flow is governedby the syngas reactions measured by online sensors or the degree ofcooling desired or both. The O2 blast tube in the lance center isshorter and inside the outer shell sufficient to create a venturi orsuction effect to pull the coal or ore mix down the lance, and wherebythe high velocity of the air/oxygen achieves thorough mixing andcombustion of coal to smelt the ore and relying on the remaining moltenslag and steel to finish smelting and conversion into iron or gas at theslag and upper region of the molten iron layer while impinging atsufficient velocity to push aside and splash molten slag onto theinterior surface of the upper entrained flow volume of the unit. Pureoxygen is not as critical with steel making or where smelting operationsare involved. In, gasification, to make syngas, pure oxygen is used inthe blast and it's desirable to make the whole of the gasificationvessel refractory lined and cyclone cleaner contiguous with thegasifying vessel in both steel-making and gasification. The gasifier orfurnace pressure vessel outer shell is water cooled and furtherinsulated against heat loss. Off-center and rectangular or ellipticalhousings are also feasible, thus concentric blast lances are not theonly configuration possible to feed ingredients and blast and achieve agood result.

In steel making, the upper shell or plenum of the furnace has a hightemperature steel alloy inner layer since pre-heating the air/oxygenblast is required to achieve steel making or smelting temperatures, suchpre-heat temperatures are well known and will vary depending on thesteel, coal quality or fuel and flux quality, but the upper plenum orshell area is designed with sufficient inner surface area of the exposedupper furnace to achieve these final blast temperatures at full loadsteel flow. Such inner steel alloy surfaces may be coated with ceramicor refractory for protection while still adequately pre-heating thesteel air-O2 mix blast without exceeding safe operating temperature ofthe inner shell lining or outer pressure vessel shell. The outer shellof the pressure vessel is steel and water cooled but also insulated onthe inside from the air-preheat flow preventing excess heat transferinto the water cooled outer shell by using refractory blanket or similarhigh temperature insulation or spray-on mixture, such detailed plenumlayering and design is well known and understood by those skilled in theart of pressure vessel, furnace and heat exchanger design combinations.

Gases leave the furnace or gasifier through a water cooled andrefractory contiguous cyclone as shown which cleans slag and/or carbonblow-by and returns it as molten slag into the crucible through therefractory lined and water cooled drop leg of the cyclone. The pressuredrop through the cyclone causes slag to travel up into this leg anamount equal to the pressure drop. At 5 psi pressure drop through thecyclone, that rise is estimated to be about 4 feet above the averageslag elevation in the crucible space. Also, such drop leg could be linedwith inductive coil to re-melt solidified slag in the leg of the cycloneshould that occur.

A refractory lined and insulated crucible below the upper air cooledmetal portion of the furnace has a center bottom tap hole for finishedcommon grade steel or to let out metals recovered from gasificationoperations, and a tap hole some distance above the floor on the sidewall of the refractory crucible to accommodate slag removal, the heightof this slag hole would be determined by design. For example, if forbasic steel containing 600 tons were to be maintained in the crucible,the crucible inner diameter the slag tap hole may be as high as 6-7feet. In the base of the crucible, there is a ceramic fine air/oxygenbubbler diffuser of sufficient diameter and flow to cause adequatecarbon reduction in the iron in the lower section of the molten ironlayer to convert smelted iron to common-grade quality steel, wherebysuch steel (or recovered metals as in gasification) flow down through anopen center hole of this diffuser and tap hole passage or ceramic pipe,such ceramic passage hole pipe is a magnetic inducing coil or plates toproduce counter forces for steel flow control to assist in the controlof steel outflow for crucible molten level control purposes or meltmaterial that might solidify in the tap hole. For gasificationapplications, the molten metal thickness, to the extent metalaccumulates, would be much less than the molten slag thickness. Therelative thickness as shown in FIG. 1 apply and is shown as if steel isbeing made.

To simplify discussion of the invention in this instance, a simplerectangular symbol is shown to represent steel and slag outlet valvesfor flow control which can be ceramic tubes surrounded withrefrigeration coils to create hole size control or ceramic plug valveposition or even ceramic flapper valve position outside the apparatus tocontrol these flows. Or, ceramic plug valves can be mounted inside andactuated by suitable long ceramic shafts for outside actuators operatingthrough flexible bellows interfaces (all not shown in detail) to enablepressurized operation of the gasifier. Any number of arrangements formetal and slag flow control are possible and are familiar to those inthe business of designing and manufacturing steel-making furnaces,processes, and specialized steel ladle valve apparatus.

A reliable method to sensing of molten metal and slag or fresh feedaccumulation in the previously mentioned U.S. Provisional PatentApplication Nos. 60/629,486 and 60/635,117 was a scanning nuclear gage,or x-rays could also be used. An alternative to scanning focused nuclearemissions or x-rays to level thickness measurement is an array of insitulaser spectrometers, just invented by others. Such a spectrometer hasbeen proposed and probably uses an air cooled diamond window towithstand the high temperatures (diamond melts at about 2.5 times moltensteel temperatures, steel melts at about 1500 C). Indeed, 5 caratartificial diamonds of high quality are available and much largerartificial diamond crystals will be available soon. This is likely largeenough a diamond crystal to pass a laser bean into and reflect offmolten steel or slag for measurement purposes. The same laser can feedoptic fibers to an array of diamond window insitu units with differentfibers sending the reflected signal back to the same reading equipmentand control room mounted sensor and computer (not shown). The advantageof the insitu laser spectrometer type sensor is it also feeds back thecomposition of the molten metal so that a picture of development intosteel vertically within the crucible is obtained. One insitu laserspectrometer sensor for slag and one for metal could suffice forsample-data level control methods for slag and steel level. With thismethod, control valves increase output until slag level drops below thesensor whereby the flow is decreased and this oscillation up and down ispart of the control method, which would be the same for the molten metaland slag interfaces. But if multiple levels are to be specified underdifferent conditions, or to have working backups, or a full picture ofsteel quality development, an array of such sensors is needed. Three inslag and molten metal are shown, but many more can be used economicallysince the same laser and computer are used for every measurement. Suchsingle data point level proximity sensors coupled with sampledata-control theory have been common use before, and such controlalgorithms can accurately control slag and metal outflows to maintaintheir proper thickness while maintaining a relatively steady valvesetting for any given load. Other types of insitu sensors can alsodetermine a picture of density variation for layer thickness such asproximity probes that vibrate to determine densities, magnetic,capacitive or resistive proximity sensors, and the like. But of these,insitu laser spectroscopic sensors are the most powerful as toinformation gained by yielding also the quality state of molten slag orsteel, especially carbon vertically within the metal molten mass. Theycan also be simple, rugged and long lasting if the window is a gascooled diamond polished flat like a small piece of glass.

In addition, an alternative to insitu sensor array, a velocity change ofa falling ball can determine levels of slag and molten metal as shown.This method of sensing velocity change is not as powerful a method aslaser spectrometers, as mentioned previously and is an awkward method.In this instance, a heavier ceramic or water cooled ball is periodicallyreleased in the gas zone and hinged acting through a flexible diaphragmfalls through an arc at various velocity rates depending if it were ingas, or molten slag or metal. Hence through velocity variations thecomputer knows where one interface starts and the other stops, thusdetermining thickness of these zones within the range of the oscillatingball. Or, two balls of different density to float on slag or steel couldbe applied instead. The computer algorithms to control these variablescan be created by those skilled in the art of syngas or steel making andare discussed further below. Thus, with this critical level measurementand other measurements noted, the direct and continuous syngas or steelmaking processes and apparatus as explained herein can be fullyautomated and optimized.

Also, steel quality can be sensed as it flows molten and hot in thetrough directly from the furnace unit (not shown). These laserspectrometer sensors to determine steel characterizes have been triedand found to be practical and is a back-up or adjunct method that can beused to continually sense final steel quality along with the insituspectrometers mentioned previously and was covered in the citedinventions.

Insitu laser sensors are being tried now in the power industry to sensecombustion gases and appear to be a practical method to sense steelmaking gases or syngas gases for more accurate control purposes. In situlaser combustion gas sensors do not need recalibration once calibrated.They do have to be gas purged to keep the optics cool, and this gaspurge rate is accounted for in the calibration phase of the instrument.For gasification, CO2 or pure O2 would be the recommended purge gas. Forsteel-making, nitrogen would be the recommended purge gas. In theinstance of making steel, control valve means to adjust air/oxygen blastrates into the top lance and bottom fine bubble diffuser and optimizingalgorithms to computer control the whole furnace process as follows inA-G below:

A. If more production is needed, the computer looks to increase steeland slag levels or fresh feed accumulation levels to adjust to a highersteel and slag flows out enabling precise levels and thickness of metaland slag or fresh fed material accumulation to be maintained within thefurnace or gasifier, and if final steel carbon is increasing perspectrometer measurements, it increases bottom bubbling air/oxygenflows. If CO is excessive, it increases the hot air/oxygen blast fromthe lance.

B. If steel carbon content too high, the computer increases bubblingair/oxygen from the base, and if that does not correct it, increases thelance air/oxygen blast as well. If it is still too high or reducingatmosphere in the furnace is getting too low (as evidenced by decreasingCO measurement), the ore mix feed is reduced or coal feed rate increasedto bring the carbon reducing capability of the diffuser within it'sacceptable range of capability.

C. For furnace molten iron level for any given ore feed rate (productionset point), the molten layer sensing enables furnace iron level to beadjusted by the steel outlet tap hole plug position or refrigeranttemperature or flow rate, eddy inducing restricting forces whichevermeans of flow control are used or necessary to be used. All three can bedesigned to operate in staggered way; eddy current first, refrigerantflow second, and use of the tapered plug force or position as a thirdmethod.

D. If steel is being made (with gasification, only carbon and flux wouldlikely be added), the steel carbon level is acceptable, but other steelchemical parameters are too high or too low, the only remedy may be achange of the ore mixture by adjusting lock hopper discharge rates (lockhoppers not shown). It will take a long time constant for these changedto show up in the final steel since there can be up to 6 hours of steelcapacity contained within the crucible for basic steel manufacturingoperations (calcium carbonate used as flux), but computer controlalgorithms can easily accommodate such time lags given the level inputs.

E. The laser spectrometer on slag monitors it for iron and carboncontent indicating an ore mix change may be needed or that more lanceblast is needed. It may be desirable to let out-of-limit carbonconditions prevail in the slag if it is the most cost effectiveoperation. The computer can be capable of calculating the costconsequences of various operation modes. As noted, this laserspectrometry is shown insitu, or lasers can sense the molten outflowitself as shown in the previously mentioned U.S. Provisional PatentApplication Nos. 60/629,486 and 60/635,117.

F. Since it's probably almost always desired to evolve to maximumpossible production capability of the furnace, the computer can alwaysbe set to an evolutionary operations standard of maximum production, sayas determined by an upper level carbon content of the final steel oriron or slag or maximum syngas flow (hot gas mass flow rate measurementmethod not shown). In this instance, the computer will slowly ramp upinput or mix feed rate and adjust crucible molten slag and iron levelsto maximize production. Maximum possible levels of slag and iron will bedetermined over time. Increasing top air/oxygen lance blast and bubblingO2 rates under the steel should maximize steel production until alimiting condition is reached (say excessive carbon in the final outputsteel) then the computer will back down production to within a safelevel such that there is a measure of control over the process using thevarious parameters measured: water vapor, O2, CO2/CO, temperatures,final laser spectrometer quality measurements of steel and slag, furnaceiron and slag level or thickness, air blast, air/oxygen bubbling rate,or ore mix compositions, steel and slag flows, syngas flows, allautomatically adjusted by the computer control system algorithmdeterminations.

G. Steel and slag weir flows (not shown) are measured since theyindicate production levels of actual steel and slag and they can alsoindicate if an upper limit has been reached or that there are moltensteel or slag flow control problems. For example, if the plug opens thetap hole more but no increased flow is noted in either slag or steel,then ether the flow control actuating methods are failing, and computerhistorical data can immediately enable the computer algorithm to alarm,and output what the operator should check first.

Thus, it can be seen that this invention teaches a very advanced methodof continuous steel making and/or gasification and uses the most moderncombination of instruments and sensors to accomplish this, and itteaches a variety of molten slag and steel level and quality sensinginstrumentation that can be used, and unique arrangements of equipmentand process to avoid the need for coke and expensive recuperator topreheat air/oxygen blast to proper temperatures. And finally,optimization algorithms are suggested such that those skilled in thecomputer programming arts and steel-making and syngas making incombination with steel process engineer experts in acid or basic steelmaking processes etc. could enable such software to take advantage ofthe instrument signals provided to gain precise and accurate controlover the process including ingredient mix ratios and all material flowsto optimize syngas and steel outflow rates with maximized quality andeconomic advantage with a minimum of labor input and capital cost.

Finally, means are suggested whereby maximum recycling of slag wastesinto useful building materials is possible by air drying slag intoclinkers, and grinding these clinkers into cement base material withcrystallized dirt already present, and adding what regular cementproduct is necessary to make a quality pre-mixed concrete aggregatebased product.

The present invention and its advantages over the prior art will be morereadily understood upon reading the following detailed description andthe appended claims with reference to the accompanying drawings.

DESCRIPTION OF THE DRAWINGS

The subject matter that is regarded as the invention is particularlypointed out and distinctly claimed in the concluding part of thespecification. The invention, however, may be best understood byreference to the following description taken in conjunction with theaccompanying drawing figures in which:

FIG. 1 is a vertical schematic section of one embodiment of the presentinvention.

FIG. 2 is a vertical schematic section of another embodiment of thepresent invention.

DETAILED DESCRIPTION OF THE INVENTION

Referring to the drawings wherein identical reference numerals denotethe same elements throughout the various views, FIG. 1 shows anapparatus 1 comprising a single vessel blast furnace that can be adirect smelting iron and steel-making apparatus or a gasificationapparatus. Generally, the present invention relates to any type ofapparatus that produces a molten by-product, such as molten slag or ash,including, but not limited to, iron or steel making apparatuses, solidwaste, coal and other types of gasifiers, waste-to-energy boilers, andcoal boilers.

When apparatus 1 is used as a gasifer, it's desirable to keep nitrogenout of the gasification reactions to avoid noxious nitrogen basedcompounds, therefore once lock hoppers (assemblies with valves notshown) are filled, it's desirable to close bubble tight lock hoppervalves and evacuate the chamber by vacuum pumps (not shown) and continueto purge lock hopers with an un-reactive gas such as CO2 tore-pressurize the lock hoppers so as to prevent undesirable gasificationreactions when oxidizing reactions take place from pure pre-heated (ifnecessary) oxygen or air-oxygen mixture addition 2 through lance 3 innerO2 feed tube 4 (shown as a line in FIG. 1). At least 3 hoppers peringredient provides the maximum practical reliability. It should benoted here that the terms “air” and “oxygen” can be used interchangeablyand either term, whether used alone or together, refers to air, pureoxygen or any other oxygen-containing substance.

Also, in feeding coal and flux or any material mix 5 to be gasified, itshould be relatively dry and finely ground material, but it does nothave to be a fine powder, as pure oxygen is highly reactive with carbonunder circumstances depicted in the invention. Therefore, as in timespast when coal was prepared (ground) and stored in large bins prior tofeeding to boiler burners, for best feed reliability this is also abetter practice for this invention utilizing large storage silo's, forexample, before feeding coal to fill the lock hoppers (not shown).

Mix feed 5 (coal, ore, and fluxes respectively) flows by gravity throughchutes (not shown) into the outer concentric space 7 of lance 3splitting around inner lance air/oxygen tube 4 (shown as line here).Lance 3 can be as large as twenty-four inches in diameter or more forfurnaces with 800,000 tons per year of steel producing ability. Alsovery high output gasifiers are possible with this design, as large as1000 MW input and possibly even double that coal feed rate as a gasifiershould be feasible since at inputs of 1000 kW/cubic foot (less than onehorsepower input per cubic inch) are feasible, that's only an entrainedflow volume 6 above the slag layer of 1000 cubic feet with a coal flowof about 130 tons per hour (depending on coal BTU content). The wellinsulated gasifier 1 is expected to achieve a hot gas efficiencyapproaching 98% (neglecting parasitic losses, the largest being O2production).

In describing the upper furnace area, in making steel, blast 2 entersthe bottom of upper plenum dimension area 8 at 2″ (plenum details notshown) passing around this plenum to pre-heat the blast and cool theplenum whereby it enters to enter lance 3 as blast 2 or pure oxygenblast 2 if making syngas. Note for steel making, blast 2 is not 100%oxygen but is only pure oxygen enhanced and pre-heated as needed toachieve high temperatures to smelt the ore mix. Similarly, whenapparatus 1 is used as a gasifier, upper plenum area 8 may be fullyrefractory lined as shown for crucible lining 9 in molten slag 10 andmolten metal mass 11 spaces. If the unit 1 is a gasifier, molten steelthickness 11 will be held to a much lesser thickness than slag thickness10. Mix 5 leaves the lance as 5′ as shown to combust and or smelt intoiron on the top layer slag 10 which is depressed as shown due to thehigh blast 2′ velocity leaving the lance 3 tube 4. Oxygen blast 2′ whichis slightly inside the lance perimeter exit mouth as shown, whichcreates a vacuum to induce mix 5′ into the burning and/or smelting zone12 beneath the lance insuring complete mixing of mix 5′ and oxygen blast2′. Lance coolant 13 enters the cooled perimeter of the lance, generallyof copper construction, (water coolant flow control not shown) as shownand if making syngas exits at the base as 13′ around the lower perimeterof copper lance 3 through nozzles (not shown) which along with pureoxygen 2′ makes unit 1 into a syngas producing device instead of asmelter/steel making device, otherwise, coolant 13 re-circulates throughthe lance as required to keep lance 3 within temperature specifications.

Water cooling details of externally insulated outer shell of apparatus 1are not shown, but such technique is well known to those skilled in theart of such pressure vessel design including hoop stress design criteriafor such high temperature pressure vessels, including insulating thisouter shell inside the area 8 if it is a plenum preheating air-O2 blastin the case of making steel. As a steel making device, the upper shellarea 8 of apparatus 1 would likely require a separate controlled coolantshould the complete unit 1 not be fully refractory lined as in makingsteel. For example, when making steel, upper plenum shell area 8 isdesigned as a plenum to preheat oxygen enhanced blast 2, whereas whengasifying, such a blast preheat plenum is not necessarily required(although it may be desirable in some instances, say with wetter fuels)so the whole inside area 8 of upper entrained flow zone 6 could berefractory lined. The outer shell of unit 1 as a pressure vessel wouldstill be water cooled and further insulated to minimize heat losses asnoted above. The inner shell of plenum area 8 could be any corrosionresistant metal but would probably be stainless steel and ceramic orrefractory spray coated for further protection but of not such thicklayer as to prevent adequate air-O2 mix preheating for steel making. Theinner or part of the other pressure vessel of area 8 would also beinsulated to preserve the pre-heat value of the blast.

The preheated air/oxygen blast 2 through center tube 4 impinges into themolten slag 10 at zone 12 combusting the coal or carbon materialproviding heat for smelting or gasification as required. This blast alsospatters slag (not shown) within the upper zone 6 which helps preservethe inner shell coating material of plenum area 8, and passes downthrough the concentric opening by gravity to impinge onto and create adepression of the molten slag 10 created by the force of air/oxygenblast 2. Typically about ten psig of air pressure would be used tocreate the high velocity blast 2′ needed including pressure drop neededto clean gases through a cyclone 14.

Inner gas flow 15′ whether from steel making or gasification passes intothe refractory lined and water cooled cyclone 14 to remove moltenparticulate matter or slag to recycle it back as molten material intoslag mass 10. The high temperatures keep the carbon and escaping slaginto a melted state as noted and which runs down leg 14′ back intomolten slag mass 10 as noted. Since there is a pressure drop thoughcyclone 14, slag 10 is drawn up into leg 14′ to some level 17approximately as shown, but such amount will vary depending upon thepressure drop designed into the cyclone 14, but about 4 feet ofelevation into leg 14′ above the average slag mass 10 top level would beexpected for a 5 psi pressure drop.

And to complete gasification reactions if no iron ore is being added butjust coal and flux as in gasification, the water cooled outer layers ofcopper lance 3 of would emit coolant stream 13 as steam water/steammixture 13′ though nozzles (not shown) around the lance perimeter atit's base to complete the gasification reactions to hydrogen and carbonmonoxide with some excess water vapor present along with CO2 andvaporized or ionized trace metals, and H2S and other vaporized compoundsand elements which are removed later from gas 15 by well known methods.The amount of steam or water 13′ emitted from periphery nozzles on lance3 will depend on the gas characteristic measured and temperature of thereaction desired and whether blast 2 is mostly air or mostly pureoxygen, but is generally minimized. Better control of either steel orgasification burn reactions can be achieved in gas 15′ or final gas 15by using new laser spectrometry emitter 19 and receiver 19′ technologywhich shoots a laser beam 20 across and through a chord segment(s) ofgas stream 15′ or 15 (multiple units would be used in an array to get acomplete picture of the gas within space 6 but only one of 19/19′ isshown) as gas 15 in the exit pipe (lasers not shown). Only about ½ of 1%of beam 20 needs to strike sensor 19′ to record nearly all the gas 15′characteristics including temperature, moisture, CO, CO2, O2, and othergas constituents. Because this measurement is laser based, once it iscalibrated, it should never need to be calibrated again, which is adistinct advantage over all other hot gas sensors to determine gascharacteristics. Conventional gas constituent sensor 18 would also beinstalled as a back-up and calibration check on spectrometer assemblies19/19′.

The lower furnace area is comprised of refractory lined crucible withinsulated refractory 9. The inner diameter of this crucible material 9could be as large as 20 feet inside diameter to accommodate say 600 tonsof steel maintained in the furnace for basic steel operations for a800,000 tons per year furnace. To control upper molten slag level ofmass 10 and molten steel level of mass 11, a scanning nuclear or x-raygage operating along a vertical chord of the crucible lined as 9 fromthe outside (not shown) can be used and is described in the previouslymentioned U.S. Provisional Patent Application Nos. 60/629,486 and60/635,117. These would not generally scan through the center of thediameter but rather off to one side as noted, or scanning a chord of thecrucible's horizontal cross section of suitable length for nuclear raypenetration through the furnace and furnace mass to detect the fullrange of molten slag 10 and steel 11 respectively, and upper fresh feedmass thickness as well (fresh material thickness not shown). This signalis feed into a computer programmed to show a complete vertical densityprofile of the vertical height measured which can be used to makecontrol decisions on inflows and outflows to the furnace to be discussedbelow. Other sensors that can accomplish this control task are discussedbelow and which have certain other advantages.

The upper layer of the molten steel molten mass 11 is expected to beconsidered as smelted iron and the lower level of 11 to be low-gradesteel created by the carbon reducing action of an oxygen blast 22 whichpasses into the base of the crucible 9 through fine bubbling diffuser 23and up though the mass of molten steel and slag as shown depicted asbubble streams 23′.

The common grade steel 21 exits the base of unit 1 through ceramic pipepassage or tap hole 33 which through most of its length is surrounded byeddy current inducing forces coil not shown which can be activated byelectricity so as to act as a countervailing force to control the exitflow of steel 21 through passage way 33. The outer tap hole area 33 issurrounded by refrigerated coil (not shown) which can have cooled fluidsat various flow rates and temperatures, adjusted by computer controlbased molten steel level computer inputs to cause the exit tap hole 33to shrink in size as required which can also control out-flows of steeland slag and the level or thickness of 10 or 11. Similar technique canbe used on slag tap hole 24″. Or, the computer can activate the actuatorof plug valves 24′ for slag and 21′ for steel, such ceramic plug flowvalves are well known in the steel making art and are usually submergedin a pan (not shown but depicted in cited inventions).

To begin operation of the furnace or gasifier, molten slag would beadded to the crucible though an upper furnace opening (not shown), andthen the hot blast 2 would commence in conjunction with the feed 5driven by blast 2 into the slag as 10. The computer would be determiningthe amount of moisture, temperature, CO2, CO, and O2 of the process gas15′ and exit gas 15 and begin to adjust feed rate 5, slag and steelflows 24 and 21 respectively and starting the adjustments of mix 5ingredient ratios or rates depending on insitu laser spectroscopicmeasurements 26 (three sensors shown) and 27 (three sensors shown but afull vertical array on the steel mass would likely be used). Other typesof insitu proximity sensors can be used to replace 26 and 27 todetermine different density characteristics of molten materials such asmolten slag 10 and metal 11 including vibrating probes, conductive andcapacitive sensors, magnetic and the like. Even the dropping ballsensors 28 (shown in raised position 28′) hinged at flexible diaphragm29 could have a combined actuator velocity sensor 30 to determinevelocity change and hence the interface location between gas in 6 andslag 10, and the interface between slag 10 and molten metal 11 and in sodoing know the positions of these interfaces. An insitu laserspectrometry sensor (details not shown) as in 27 could also be attachedto such an oscillating ball 28 to sense constituent elements of slag 10and steel 11 as ball 28 is moved through slag 10 and steel 11 andpassing the fiber optic signals into and out through a hollow arm of 28.Even multiple floats (not shown) like ball 28 designed to float on theslag and steel interface layers respectively with units 30 designed todetermine floating position could be used. Those skilled in the art ofapplying such specialty sensors will know the most cost effective andreliable combination of such instruments. The previously mentioned U.S.Provisional Patent Application Nos. 60/629,486 and 60/635,117 illustratereliable and preferred methods, and this invention illustrates otherpreferred devices, like insitu laser spectrometers, that can sensemolten slag 11 and molten metals 10 depths and quality and which byvirtue of their design characteristic of using a single emitter andsensor at the computer and fiber optics to a variety of units arepossible, including exposed outflows of steel and stag. It is believedlaser spectrometry as detailed here will eventually be very cheap andpowerful sensing technology for these purposes applying many suchsensors simultaneously to these processes.

Because there is such a long time constant for turnover of steel 11within the crucible, about 6 hours, previous data and experience insteel operations contained within the computer data base, plus knownexperience and nuances about steel making programmed into the computer,enables quite accurate initial conditions for all the control variablesto be set such as pulverized coal, flux, and ore ratios to the total mix5 and what blast 2 is appropriate for what total feed mix flow 5selected. The final measurements of the laser spectrometers and outletgas 15, of CO2, CO, and temperature and other gases will enable thecomputer to bring the whole process under control and then fine tune theprocess for best steel quality consistent with carbon losses in themolten ash and needed production level.

If more production is needed the computer looks to see if it canincrease steel 11 and slag levels 10 and if it can, increases the steel11 and slag masses 10 in the crucible 9, and then it adjusts to a higherslag and steel flows 24 and 21 respectively. And if final carbon isincreasing per insitu laser spectrometer measurements 27 or externallaser spectrometer (not shown) that measures steel quality, it increasesbubbling air/oxygen flow 22 and if CO is increasing, it increases thehot air/oxygen blast 2.

If the steel carbon level is acceptable as measured by steel laserspectrometer 27, but other steel chemical parameters are too high or toolow, a remedy may be a change of the flux mixture of 5. Because theremay be up to 6 hours of steel production retained in the crucible 9 forbasic processes, it will take a long time for these changes to show upin the final steel 21, but it is still capable of automatic control andoptimization by the computer since the computer clock can wait theseintervals to check final results from the spectrometers.

If the laser spectrometer 26 used on slag indicates an ore mix 5, ratiochange may be needed or that production can be increased, under blast 22is increased to reduce slag carbon content. Or it may be desirable tolet slag carbon go out of limit to achieve the production level desired.Those skilled in the art of steel making will enable the computerprogrammer to fine tune the logic to optimally control the process.

Since it's almost always desired to evolve to maximum possibleproduction of syngas or steel, the computer can always be set to aevolutionary operations standard of maximum production say as determinedby an upper level steel 21 carbon content. In this instance, thecomputer will slowly ramp up input feed 5 and adjust slag and steel masslevels 10 and 11 as noted to higher mass levels in the crucible 9 whileincreasing top blast 2′, mix feed 5, and bubbling blast 22 until anupper limit of any one of these parameters is reached such that it isthen known steel 21 carbon content will start to rise or gas qualitystarts to fall as determined by CO and CO2 contents, then the computerwill back down production to within a safe production level such thatthere is a measure of control over the process using the parameters ofCO2/CO, final spectrometer measurements 27 and 26 of steel and slagrespectively or laser spectrometers pointed down onto the trough flowsof slag 24 and steel 21 (lasers and troughs not shown).

Steel and slag weir notch flow levels (apparatus not shown) are measuredwith a proximity level device (not shown) such as a non-contacting radaror fluidic sensor can measure production levels of actual steel 21 andslag 24 which can indicate an upper limit has been reached or that flowcontrols are malfunctioning. For example, if the plug opens the tap holemore but no increased flow is noted in either slag 24 or steel 21, thenether the tap hole is too small, the plug is malfunctioning, or a limithas been reached, and computer historical data can immediately enablethe computer algorithm to manage a determination and alarm output whichthe operator then evaluates. All of the various sensor measurements canbe programmed to alarm if extremes in their condition are reached.

Other variations of the invention are possible, such as rectangular,elliptical cross section shapes for gasifier 1 and with lances 3 to oneside and feed into lances on one side and blast tube 3 the other withblast to one side and ingredients to the other and variousconfigurations for steam and water blast for gasification (notnecessarily a symmetrical blast 13′ from the lance 3 itself). But theprevious description is a least cost and most compact or volumetricallyefficient way to make the invention for an integrated syngas and/orsteel making operations. And in steel-making, unit 1 is used inconjunction with a sizable power boiler (not shown), such boiler havingseveral other large pulverized coal burners added to enhance profitsfrom power operations, while the power boiler fully cleans up theemissions from steel making through the boiler's comprehensive emissionsreducing apparatus on the boiler stack gases. The present invention iscapable of a completely hands-off automatic control over thesteel-making or syngas making process in a cost effective manner. It'sintensity of operation and process and apparatus arrangement achieves acompact technology, as noted, and minimized capital cost apparatus. Forsteel-making it doesn't require expensive coke to operate, onlycost-effective ground-up coal either as a gasifier or a steel-making.

Referring now to FIG. 2 a second embodiment of the present invention isshown. This embodiment relates to any type of apparatus that produces amolten by-product, such as molten slag or ash, including, but notlimited to, iron or steel making apparatuses, solid waste, coal andother types of gasifiers, waste-to-energy boilers, and coal boilers.However, by way of example and for purposes of illustration, FIG. 2depicts a gasifier. As such, it doesn't describe the scanning nucleargage described above, as it only needs to be a fixed slag nuclear gagesensing molten slag level over definite and limited range of levels. Andthere are no multiple outlets of slag and steel in a simple gasifier,just a single slag outlet should generally be needed. However, if therewere a lot of metal in the coal feed, the gasifier crucible could bearranged to be like a steel-making one with multiple molten outlets withmaterial separation generally depending on density difference andaccumulating layers of different materials which would require ascanning nuclear gage in this instance to enable individual control ofthe out flow rates. But the resistive heating or other methods ofheating of the crucible molten material and other machine elements shownapply to both steel making and gasifier as does the slag recyclingapparatus achieved through cooling and clinkering described herein.Thus, no other specific references to steel making will be made in thefollowing description.

Referring to FIG. 2, a gasifier 1 is shown as a low pressure unit andthus represents a simple, low cost version of a gasifier. This gasifieris made low cost in part by using a simple low pressure (e.g., about 20psig) air-lock rotary feeder 2. For higher cost high-pressure versions,multiple lock hopper feed units with unloader/feeders (not shown) wouldbe substituted for feeder 2. But overall, a high pressure version wouldstill be more economic than existing gasifiers due to savings in slagdischarge apparatus and more accurate control possible through advancedsensing and this invention's dry feed process design.

Dry fuel mixture 4 is fed through rotary feeder 2 down though the insideof cooled copper lance 3 (copper feed lances are common in the steelindustry to inject gases and fuel into smelting and steel-makingoperations) as fuel 5 falls by gravity and is blasted atop the slag mass6. This molten slag mass 6 also provides a “fly-wheel” effect tolevelize the effects of variations in fuel quality to gasification, acommon problem with boiler burners. Air blast 7 cleans the materialsfrom the feeder compartments and provides a purge of air or oxygen forthe inside 8 of lance 3. It should be noted that fuel 4 can be a widerange of fuel quality, such as municipal solid wastes. Various fluxescan be added with the fuel 4 to remove sulfur and other metals and canbe adjusted accordingly.

Lance 3 has air passages 9 to take air or oxygen oxidizer blast 10 tothe base of the lance as blast 11 angled across the incoming fuel flowto cause through mixing of the feed 5 and oxidizer blast 10 around thelance periphery which creates a very hot fire at 12 atop the molten slagmass 6 in the 2650 F range or at least to the limestone calcinationtemperature of about 2650 F to insure that any lime flux added with fuelmixture 5 is reacted to reduce sulfur in the burning fuel whereby thecalcium ions Ca react with the sulfur ions S to form CaSO4 or calciumsulfate. Quicklime CaO is also formed from Ca un-reacted with S andcomes out in the slag discharge 13. To control the carbon content ofslag discharge 13, fiber optic laser spectrometry sensor 13′ can bouncesignal 13″ off slag flow 13 and that carbon content signal can be usedto control the rate of oxidizer bubbling 26. More about fiber opticlaser spectrometry sensing will be discussed later for control of thegasifier.

The outside of lance 3 is water or steam cooled by concentric passageway14 through which water or steam 15 flows which is emitted radically fromthe lance perimeter and shown which reacts with the fire passing upthough entrained zone 16 to cause gasification reactions within theentrained flow zone known as 12 and 16. Final entrained flow gas and ashand slag particles 18 leave entrained flow zone 16 to be cleaned inprimary hot cyclone 17 and leave as hot gas 18′. If blasts 7 and 10 arepure oxygen, gas 18′ will be classified as a syngas and be principallyhydrogen and carbon monoxide with a small amount of CO2 and other tracegases. If blasts 7 and 10 are air based, gas 18 will have a lower Btuvalue and be like a producer gas. Low Btu gas is most economic forboiler power applications where the extra volume due to nitrogen presentin the gas is not a problem. Thus much less apparatus is needed as noexpensive air separation unit is required. Well insulated and watercooled on it's outer skin, gasifier 1 can have a high hot gas efficiencyup to 98%. Thus, close coupled to boilers there is no power efficiencyloss due to gasifying first, yet the boiler can run much cleanerthroughout its operating life reducing maintenance and soot blowing.

Ash and slag captured by cyclone 17 passes down the cyclone leg 19,which is shown with embedded electric heaters 20 which are also in thewalls of the cyclone 17 as well to insure the ash stays molten shouldtemperatures fall below slagging temperatures. The electric heaters 20can be any suitable heating means such as resistive or inductionheaters. Depending on the pressure drop through cyclone 17, molten slag6 in crucible 21 will be drawn up into the cyclone discharge leg 19 to alevel 22, about as shown, i.e., the molten slag bed 6 is in effect theseal for the cyclone discharge leg 19. This unique sealing method isadvantageous because it makes hot gas cyclone 17 maximally effective incleaning gas. About a 5 psi pressure drop would be ascribed to cycloneoperations to insure a properly cleaned gas 18′ before sending theprimary cleaned gas on to other operations, which could be to boilerfurnace combustors or syngas cleaning and conversion operations.

The gasifier temperature and oxygen/coal or carbon ratio is measuredthrough appropriate flow measurements devices which can be the speed ofthe feeder 2 or orifices on blasts 7 and 10 respectively (not shown) andcontrolled by adjusting fuel feed using feeder 2 speed and blast basedon gas temperature and gas constituent measurements as measured by fiberoptic laser spectroscopy shown as emitter 23, laser beam 24 and receiver25 located in the upper area of the gasifier 1 and/or emitter 23′, laserbeam 24′, and receiver 25′ located in exit pipe 26′. The lenses of thesebeams are air or O2 purged (not shown) depending on which blast gas isused, or some combination blast. The sensing and control computer is notshown but the whole apparatus would be as made by ZoloBOSS or equal andgenerally up to eighteen or so points across the entrained flow zone 16(only three such sensor combinations are shown) can be sensed andmeasured by the computer simultaneously using sample data controltechniques including. This for example, should it be desirable to runthe gasifier entrained flow region 12 and 16 highly reductive atmospherethere, that is a heavily soot gas 18 prior to cyclone cleaning, fiberoptic laser emitter 23′, beam 24′ and receiver 25′ cleaned gas 18′ exitpipe 26′ would be installed. However, because so many points areavailable from the ZoloBOSS system, exit gas 18′ would always bemeasured in any event since it's gas constituents and temperature andmoisture measured by emitter 23′, beam 24′, receiver 25′ are adequate tocontrol the gasifier if zone 16 laser units become fouled with soot.Also, a heavily carbonaceous soot gas 18 may be desirable from anemissions reduction standpoint to absorb heavy metals and the like,including mercury. Salts can also be added with fuel feed 4, forexample, to ionize elemental mercury for easier scrubbing within thestack gas clean-up system of a boiler.

Only about ½ percent of the emitted laser light 24 needs to reach thereceiver 25 to measure gas constituents. Thus, dirty gas streams withingasifiers can be measured with this technique, and according to themanufacturer, laser spectroscopy never has to be recalibrated as ameasurement technique once set up. And depending on the laser used, itmeasures CO2, CO, O2, moisture, and combustion temperature. Thus, if thetemperature is too low, the blast 10 can be increased to produce morecomplete combustion and thus hotter conditions in zone 12 which alsoproduces more CO2 in the final gas un-cleaned gas 18. Thus if the CO2/COratio is too high, the oxygen/coal mass ratio can be adjusted down. Butbecause of the dry fuel feed and comprehensive sensing and controls,these measurements enable the control computer to fine tune operationsto minimize CO2 in the final cleaned gas 18′. And the close coupledcyclone 17 will take out any ash and slag blow-by 17′ and recirculate itto the crucible slag mass 6. Similarly, excess carbon can bespectroscopic sensed in the final slag 13 as noted, the computer canthen increase oxidizer rate 26 through ceramic bubbler distributor 27 asbubbles 28 to react any excess carbon in the slag discharge 13.

Slag flow control out can be by a ceramic plug valve 29 as used in thesteel industry or by refrigeration coils 30 used to freeze the tap hole31 smaller, or let it melt to a larger tap hole as required on thedischarge end of discharge tap hole 31 as noted. This slag outflow 13 iscontrolled to maintain a constant slag level 6 and is controlled bytypical fixed and inclined nuclear level gage generally comprised ofemitter 32, nuclear ray 33 and receiver 34, such control systems wellknown in the art, that is 33 signal received gets less as levelincreases so valve 29 is opened to bring the level back down or theopposite logic is also true. With refrigerant 30, if the level of 6increases, less refrigerant flows and the tap hole in the finaldischarge area 13 enlarges to bring the level of 6 back down, or againthe opposite logic is true. Tap hole 31 also has electric heaters 35′(which can be any suitable heater such as resistive or inductionheaters) imbedded to insure the tap hole stays open or for start-uppurposes.

Crucible 21 also has electric heaters 35 to maintain molten conditionseither at start-up or in operations. Crucible 21 and the whole upperareas of gasifier 1 would be refractory lined, insulated, and the outershells water cooled and have an outer layer of insulation, all not shownin detail on the drawing. Also, the lower crucible 21 is shown welded tothe upper gasifier area 1 with flange 36 to define a single vesselfurnace. They can be easily separated for shut down maintenance byburning off the weld at flange 36. Generally, preferred construction is100% welded. No bolted flanges are used to prevent gas leakage and lowerthe cost of construction. Welds are quickly removed to disassemble forshutdown maintenance.

Another advantage of this invention is it enables 100% recycling of slag13 which is made possible by processes similar to what is used in thecement industry, that is by cooling and clinkering the slag and storingand for later milling into a cementous products where additionalamendments and cement can be added to make a products useful in buildingroads and foundations and the like. A preferred cooling and emissionssystem is described following.

As can be seen in FIG. 2, slag 13 falls by gravity into gas cooler 37through opening 38 onto its air-cooled pin-hole grate or equal 39whereby clinkers 40 are formed from air cooling effects and are keptmoving along the grate by an oscillating pusher 41 actuated by motor 42.Blower fan 43 cooperates with ID fan 44 through pressure sensor 45 toinsure a balanced air feed and discharge so induced air 46 through theslag inlet is kept to a minimum. Cooled and clinkerized slag 40 passesthough crusher 47 and air-lock rotary valve 48 as cooled crushed clinker49 which is transported away by conveyor 50 shown as an arrowed line tostorage to be later milled and mixed to make cementous products as notedabove. These cement plant mixing and blending processes are well knownand so are not described here.

Temperature sensors to control pressurized air flow 51 and final clinker49 temperature are not shown but are well known in the art. Hot gases 52have heat recovered by unit 53, and the gases are cleaned byelectrostatic precipitator and scrubber unit 54 before passing throughID fan 44 to stack 55.

While specific embodiments of the present invention have been described,it will be apparent to those skilled in the art that variousmodifications thereto can be made without departing from the spirit andscope of the invention as defined in the appended claims.

1. A blast furnace comprising: a vessel including a crucible formedtherein; means for introducing fuel and oxygen into said crucible; andmeans for determining density characteristics of molten material insidesaid crucible.
 2. The blast furnace of claim 1 wherein said means fordetermining density characteristics of molten material includes avertical array of laser spectrometry sensors mounted in said crucible.3. The blast furnace of claim 1 wherein said means for determiningdensity characteristics of molten material includes an oscillating ballsensor located in said crucible.
 4. The blast furnace of claim 1 whereinsaid means for determining density characteristics of molten materialincludes an inclined nuclear level gage.
 5. The blast furnace of claim 1further comprising a cyclone positioned adjacent to said vessel forremoving particulate matter from hot gas discharged from said vessel. 6.The blast furnace of claim 5 wherein said cyclone includes a leg havingan end that is immersed in molten material in said crucible.
 7. Theblast furnace of claim 6 further comprising means for heating saidcyclone and said leg.
 8. The blast furnace of claim 7 wherein said meansfor heating comprises electric heaters.
 9. The blast furnace of claim 1further comprising means for measuring characteristics of hot gas insaid vessel.
 10. The blast furnace of claim 9 wherein said means formeasuring characteristics of hot gas include a laser spectrometryemitter and receiver mounted on said vessel.
 11. The blast furnace ofclaim 1 wherein said crucible includes a tap hole for discharging moltenmaterial therefrom.
 12. The blast furnace of claim 11 further comprisingmeans for heating said tap hole to insure said tap hole stays open. 13.The blast furnace of claim 12 wherein said means for heating compriseselectric heaters.
 14. The blast furnace of claim 11 further comprisingmeans for cooling and clinkering molten material discharged from saidtap hole.
 15. The blast furnace of claim 1 further comprising means forheating said crucible.
 16. The blast furnace of claim 15 wherein saidmeans for heating comprises electric heaters.
 17. A process comprising:providing a vessel including a crucible formed therein; introducing fueland oxygen into said crucible; combusting said fuel in said crucible toproduce molten material; and determining density characteristics ofmolten material inside said crucible.
 18. The process of claim 17further comprising adjusting the input of fuel and/or oxygen into saidcrucible based on the density characteristics of molten material insidesaid crucible.
 19. The process of claim 18 further comprising usinglaser spectrometry to measure characteristics of hot gas inside oroutside of said vessel.
 20. The process of claim 18 further comprisingdischarging molten material from said crucible and cooling andclinkering molten material discharged from said crucible.